FacebookTwitterYouTube RSS Feed

The long and short of optical time keeping

Event Details

Event Dates: 

Wednesday, December 3, 2014 - 4:00pm

Seminar Location: 

  • Duane Physics Room G1B20

Speaker Name(s): 

Scott Diddams

Speaker Affiliation(s): 

University of Colorado Boulder
Seminar Type/Subject

Scientific Seminar Type: 

  • Physics Department Colloquium

Event Details & Abstract: 

In the past decade, clocks “ticking” at optical frequencies have surpassed in performance their much slower microwave counterparts.  The implication is that time intervals can now be sub-divided to below the femtosecond (10-15 s) that represents a typical optical cycle.   In this new generation of clocks, a laser plays the role of the pendulum, which has its frequency guided on long timescales by an atomic reference transition.  A laser frequency comb functions as the clockwork that accumulates optical cycles in order to ultimately realize a second.

In this talk, I will provide an overview of the science and technology behind optical clocks, with a focus on practical and fundamental limitations to timing precision on long and short timescales.  In particular, I will highlight recent developments that provide a means to synthesize signals from the radio frequencies to millimeter waves with attosecond (10-18 s) timing precision.  Finally, I will attempt to offer some perspective on the challenges and opportunities for optical timekeeping that might lie ahead.  Along these lines, I will describe recent experiments with a new class of low-noise lasers and frequency combs based on monolithic microresonators.  Among their benefits, these chip-scale devices have the potential to significantly reduce the bulk, cost, and complexity of key components needed to move optical timing beyond the research lab.